The present invention relates to image-based check processing, and is particularly directed to an image-based check processing system and a method of operating an image-based check processing system to test focus of an imaging camera.
A typical image-based check processing system includes a document transport path along which financial document items can be transported from an upstream end to a downstream end. An imaging camera is disposed along one side of the document transport path to capture images of financial document items moving past the imaging camera. The imaging camera has an optical system which is focused so that quality images of the financial document items can be captured.
A known way to focus the optical system of the imaging camera is to make focus adjustments during manufacture of the image-based check processing system. This may be accomplished by capturing an image of a focus test document, analyzing the image of the focus test document, and then making any necessary focus adjustments. As an alternative to making focus adjustments during manufacturing of the image-based check processing system, an image of the focus test document may be captured and analyzed by a field service engineer when the image-based check processing system is installed in the field. Another known way to focus the optical system of the imaging camera is to use focus test patterns which are printed on batch headers and batch trailers. In this case, images of the focus test patterns on the batch headers and the batch trailers are captured and analyzed only at the start and the end of each batch of financial document items.
A disadvantage in the known ways of focusing the optical system of an imaging camera is that the optical system may go out of focus during operation of the image-based check processing system. When this occurs, poor quality images of financial document items will be captured. Poor quality images of financial document items will usually continue to be captured and remain undetected until the optical system of the imaging camera is adjusted back into focus. For example, in the case of the focus test patterns on the batch headers and the batch trailers, the capture of poor quality images of financial document items will usually continue for at least the entire batch of financial document items until the next batch of financial document items is processed. It would be desirable to provide a way of adjusting the focus of the optical system of the imaging camera so as to eliminate, or at least, reduce the capture of poor quality images of financial document items during operation of the image-based check processing system.